Automation equipment involving transferring pieces from one station to another station has been used extensively. Such equipment has generally involved means for taking a piece, such as an automotive part being manufactured, from a first die by suitable gripping means and transferring the piece held to a second die.
Present transfer machines have generally been controlled by fixed programs in a computer programmed to operate in accordance with a predetermined sequence of operations. In a normal manufacturing plant involving manufacture of automotive parts, for example, it is very difficult to maintain extremely close tolerances required for an operation of a programmed system. Because of many variable factors involved, it is often necessary to adjust one of the functions relating to a particular operation involving the transfer of parts. The operations in a typical transfer apparatus may include, for example, the operation of the gripping means, movement of the parts by a shuttle or extendible arm and rotation of the parts.
In such prior art systems, if any one of the operating functions has to be adjusted, it is often necessary to stop production so that adequate changes may be made in the controlling program. Generally, the requirement for even a minor change in a program involves skilled personnel not always readily available.
Another problem in many existing systems is that the various controls involving the transfer apparatus and controls relating to "in-die" operations are located in different places. This is necessitated by the placement of the belt conveyors and other line equipment. This often requires personnel to move back and forth between different locations to perform the necessary adjustments.
Most transfer machines are operated in a series or cascade manner. This means that one function must be completed before a subsequent function may be started. This generally involves a maximum time to complete all the operations. In addition to this, when one function is changed by varying an electrical circuit, it often affects the other functions involved which then must also be adjusted.